The census of interstellar complex organic molecules in the Class I hot corino of SVS13-A

Abstract

We present the first census of the interstellar Complex Organic Molecules (iCOMs) in the low-mass Class I protostar SVS13-A, obtained by analysing data from the IRAM-30m Large Project ASAI (Astrochemical Surveys At IRAM). They consist of an high-sensitivity unbiased spectral survey at the 1mm, 2mm and 3mm IRAM bands. We detected five iCOMs: acetaldehyde (CH 3 CHO), methyl formate (HCOOCH 3 ), dimethyl ether (CH 3 OCH 3 ), ethanol (CH 3 CH 2 OH) and formamide (NH 2 CHO). In addition we searched for other iCOMs and ketene (H 2 CCO), formic acid (HCOOH) and methoxy (CH 3 O), whose only ketene was detected. The numerous detected lines, from 5 to 37 depending on the species, cover a large upper level energy range, between 15 and 254 K. This allowed us to carry out a rotational diagram analysis and derive rotational temperatures between 35 and 110 K, and column densities between 3 × 10 15 and 1 × 10 17 cm −2 on the 0. 3 size previously determined by interferometric observations of glycolaldehyde. These new observations clearly demonstrate the presence of a rich chemistry in the hot corino towards SVS13-A. The measured iCOMs abundances were compared to other Class 0 and I hot corinos, as well as comets, previously published in the literature. We find evidence that (i) SVS13-A is as chemically rich as younger Class 0 protostars, and (ii) the iCOMs relative abundances do not substantially evolve during the protostellar phase.

Formation of complex molecules in translucent clouds: acetaldehyde, vinyl alcohol, ketene, and ethanol via “nonenergetic” processing of C2H2ice

“…The consecutive hydrogenation of glycolaldehyde forming ethylene glycol has been experimentally confirmed on grain surfaces under molecular cloud conditions . A similar chemical link can also be seen for species, such as ketene, acetaldehyde, and ethanol, which have been observed altogether toward several protostellar sources, such as NGC 7129 FIRS 2, SVS13-A, IRAS 16923-2422B, and L1157-B1 shock regions (Bisschop et al 2007;Fuente et al 2014;Lefloch et al 2017;Bianchi et al 2018). These species are topic of the present study.…”

FAUST I. The hot corino at the heart of the prototypical Class I protostar L1551 IRS5

“…Here we show that even in Class I hot corinos the estimation of the column density of methanol assuming that the 13 C isotopologue lines are optically thin can be inaccurate. This fact could explain the contradictory results found by Bianchi et al (2019b) when comparing the iCOM abundances normalised to methanol in different Class 0 and I protostars. A reliable measure requires the 18 O methanol isotopologue detection.…”

Unidentified infrared emission features in mid-infrared spectrum of comet 21P/Giacobini-Zinner

“…During the final stage of the satellite formation, many icy satellitesimals (small bodies) are present as building blocks of icy satellites in the disk. As demonstrated by previous studies about the chemical evolution of interstellar media, various kinds of complex organic molecules have been observed in warm environments (> 100 K), such as hot molecular cores (e.g.,Choudhury et al 2015;Bergner et al 2017;Bianchi et al 2019). Therefore, complex organic molecules formed by gas-phase chemical reactions under warm conditions (in the earlier evolutional stage of a circumplanetary disk) might finally be frozen and incorporated into satellitesimals as the circumplanetary disk cools down.…”